Most Recent Weekly Report: 18 March-24 March 2015

SVERT reported that satellite images over Snow, a volcano of Chirpoi, showed faint stream-and-gas emissions on 16 March and a thermal anomaly during 17-20 March. Cloud cover obscured views on other days during 21-23 March. The Aviation Color Code remained at Yellow.

Most Recent Bulletin Report: December 2013 (BGVN 38:12)

On 6 November 1986, weak fumarolic activity was observed during an aerial survey (SEAN 12:04). The Sakhalin Volcanic Eruption Response Team (SVERT) noted that emissions were again observed in November 2012. This report covers steam-and-gas plumes and emissions and thermal alerts between 20 November 2012 and 30 April 2014.

SVERT's monitoring of Chirpoi is hampered by the lack of surface instruments or seismic network. The volcano is primarily monitored by satellites; cloud cover, however, often prevents space-borne observations. The location of Chirpoi in the Kuril Islands is shown in figure 1.

Figure 1. Map showing location of Chirpoi. Courtesy of Google Earth.

SVERT reported thermal anomalies at a volcano of Chirpoi called Snow, starting on 17 November 2012. Periods of steam-and-gas began on 15 December 2012. This activity continued through at least April 2014, based upon analysis of satellite images (table 1). Cloud cover often obscured views of the volcano.

Table 1. Steam-and-gas plumes and emissions from Snow, a Chirpoi volcano, between 21 November 2012 and 30 April 2014, based on analysis of satellite images. Cloud cover frequently prevented observations. Courtesy of SVERT.

Year

Dates

Plume drift

2012

15 and 19 Dec

na

2013

9 and 11 Jan

na

2013

1, 7, 10, 14-15, 19-22, 25 Feb

na

2013

1, 3, 5 Mar

na

2013

23-Jul

na

2013

9 and 12 Aug

na

2013

22-23, 29-31 Oct

na

2013

4, 6, 25 Nov

Drifted 90 km SE on 25 Nov

2014

15, 20, and 27 Mar

na

2014

13-Apr

na

A search of MODVOLC thermal alerts at Chirpoi since 1980 found no such alerts until a they began at Snow on 11 November 2012. Between that date and 24 December 2012, many thermal alerts were reported. According to SVERT, this may have indicated a lava flow on the SE flank. No further alerts were reported until 8 July 2013; between 8 July and October 2013, thermal alerts were issued on six days. The only alerts between November 2013 and 30 April 2014 were on 10 March, 27-28 March, and 14, 16, 18, 21, 27, 29-30 April 2014.

Based on SVERT weekly reports on 12 and 19 November 2012, the Aviation Color Code increased from Green to Yellow between 5 and 19 November 2012, and remained Yellow through at least April 2014. (Green indicates a normal, non-eruptive state; Yellow indicates elevated unrest above background level.)

Weekly Reports

18 March-24 March 2015

SVERT reported that satellite images over Snow, a volcano of Chirpoi, showed faint stream-and-gas emissions on 16 March and a thermal anomaly during 17-20 March. Cloud cover obscured views on other days during 21-23 March. The Aviation Color Code remained at Yellow.

SVERT reported that satellite images over Snow, a volcano of Chirpoi, showed a thermal anomaly during 9, 14, and 15 March. Cloud cover obscured views on other days during 9-16 March. The Aviation Color Code remained at Yellow.

SVERT reported that satellite images over Snow, a volcano of Chirpoi, showed a thermal anomaly during 3-5 and 7-8 March. Cloud cover obscured views on other days during 2-9 March. The Aviation Color Code remained at Yellow.

SVERT reported that satellite images over Snow, a volcano of Chirpoi, showed gas-and-steam emissions on 23 February and a thermal anomaly on 23 and 25 February. Cloud cover obscured views on other days during 23 February-2 March. The Aviation Color Code remained at Yellow.

SVERT reported that satellite images over Snow, a volcano of Chirpoi, showed gas-and-steam emissions on 19 February and a thermal anomaly on 21 February. Cloud cover obscured views on other days during 16-23 February. The Aviation Color Code remained at Yellow.

SVERT reported that satellite images over Snow, a volcano of Chirpoi, showed a thermal anomaly on 9 and 11 February. Cloud cover obscured views during 10 and 12-16 February. The Aviation Color Code remained at Yellow.

SVERT reported that satellite images over Snow, a volcano of Chirpoi, showed a thermal anomaly during 20-21 and 25 January. Cloud cover obscured views on other days during 19-26 January. The Aviation Color Code remained at Yellow.

SVERT reported that satellite images over Snow, a volcano of Chirpoi, showed a thermal anomaly during 10-11 January. Cloud cover obscured views on other days during 5-12 January. The Aviation Color Code remained at Yellow.

SVERT reported that satellite images over Snow, a volcano of Chirpoi, showed a thermal anomaly on 4 January. Cloud cover obscured views on other days during 30 December-5 January. The Aviation Color Code remained at Yellow.

SVERT reported that satellite images over Snow, a volcano of Chirpoi, showed a thermal anomaly on 23 and 25 December. Cloud cover obscured views on other days during 22-29 December. The Aviation Color Code remained at Yellow.

SVERT reported that satellite images over Snow, a volcano of Chirpoi, showed a thermal anomaly during 2-5 December. Cloud cover obscured views on other days during 1-8 December. The Aviation Color Code remained at Yellow.

SVERT reported that satellite images over Snow, a volcano of Chirpoi, showed a thermal anomaly on 27 November. Cloud cover obscured views on other days during 25 November-1 December. The Aviation Color Code remained at Yellow.

SVERT reported that satellite images over Snow, a volcano of Chirpoi, showed a weak thermal anomaly during 17-18 November. Cloud cover obscured views on other days during 19-24 November. The Aviation Color Code remained at Yellow.

SVERT reported that satellite images over Snow, a volcano of Chirpoi, showed a weak thermal anomaly on 16 November. Cloud cover obscured views on other days during 11-17 November. The Aviation Color Code remained at Yellow.

SVERT reported that satellite images over Snow, a volcano of Chirpoi, showed a thermal anomaly during 15-16 October. Cloud cover obscured views on other days during 14-20 October. The Aviation Color Code remained at Yellow.

SVERT reported that satellite images over Snow, a volcano of Chirpoi, showed a thermal anomaly on 6, 9, and 12 October. Cloud cover obscured views on other days during 7-13 October. The Aviation Color Code remained at Yellow.

During 1 to 16 September thermal anomalies were detected from Chirpoi in satellite images when clear conditions permitted. On 4 September SVERT increased the Aviation Color Code from Green to Yellow due to renewed activity including thermal anomalies. Gas-and-steam plumes were visible on 11 and 15-16 September.

In a 5 June report, SVERT summarized activity at Snow, a volcano of Chirpoi, over the previous two years: an effusive eruption started on 10 November 2012, producing steam-and-gas emissions and thermal anomalies thorough April 2013; the volcano was quiet; steam-and-gas emissions and thermal anomalies were again detected starting on 12 July 2013, suggesting a new period of lava effusion. Weak thermal anomalies during 2-4 June implied cooling lava flows. The Aviation Color Code was lowered to Green.

SVERT reported that satellite images over Snow, a volcano of Chirpoi, detected a thermal anomaly on 7 and 9 May. Cloud cover obscured views on other days during 5-12 May. The Aviation Color Code remained at Yellow.

SVERT reported that satellite images over Snow, a volcano of Chirpoi, detected a thermal anomaly on 21 and 27 April. Cloud cover obscured views on the other days during 22-28 April. The Aviation Color Code remained at Yellow.

SVERT reported that satellite images over Snow, a volcano of Chirpoi, detected a thermal anomaly on 14, 16, and 18 April. Cloud cover obscured views on the other days during 15-21 April. The Aviation Color Code remained at Yellow.

SVERT reported that on 13 April satellite images over Snow, a volcano of Chirpoi, detected steam-and-gas emissions. Cloud cover obscured views on the other days during 9-15 April. The Aviation Color Code remained at Yellow.

SVERT reported that on 27 March satellite images over Snow, a volcano of Chirpoi, detected a thermal anomaly and a steam-and-gas plume drifting more than 50 km SE. A weak thermal anomaly was detected on 28 March. Cloud cover obscured views on the other days during 24-31 March. The Aviation Color Code remained at Yellow.

SVERT reported that a steam-and-gas plume from Snow, a volcano of Chirpoi, was detected in satellite images drifting 150 km SE on 20 March. Cloud cover obscured views during 17-19 and 21-24 March. The Aviation Color Code remained at Yellow.

SVERT reported that a thermal anomaly over Snow, a volcano of Chirpoi, was detected in satellite images during 10-12 March. Diffuse steam-and-gas emissions were observed on 15 March. Cloud cover obscured views during 13-14 and 16-17 March. The Aviation Color Code remained at Yellow.

SVERT reported that a thermal anomaly over Snow, a volcano of Chirpoi, was detected in satellite images on 3 March. Cloud cover obscured views during 4-10 March. The Aviation Color Code remained at Yellow.

SVERT reported that a thermal anomaly over Snow, a volcano of Chirpoi, was detected in satellite images on 25 and 27 February. Cloud cover obscured views on the other days during 24 February-3 March. The Aviation Color Code remained at Yellow.

SVERT reported that a thermal anomaly over Snow, a volcano of Chirpoi, was detected in satellite images during 19-20 February. Cloud cover obscured views on the other days during 17-24 February. The Aviation Color Code remained at Yellow.

SVERT reported that a thermal anomaly over Snow, a volcano of Chirpoi, was detected in satellite images during 11-12 February. Cloud cover obscured views during 13-17 February. The Aviation Color Code remained at Yellow.

SVERT reported that a thermal anomaly over Snow, a volcano of Chirpoi, was detected in satellite images during 6 and 8-9 February. Cloud cover obscured views on other days during 4-10 February. The Aviation Color Code remained at Yellow.

SVERT reported that a thermal anomaly over Snow, a volcano of Chirpoi, was detected in satellite images during 21-23 January. Cloud cover obscured views during 24-27 January. The Aviation Color Code remained at Yellow.

SVERT reported that a thermal anomaly over Snow, a volcano of Chirpoi, was detected in satellite images during 15-16 January. Cloud cover obscured views on the other days during 14-20 January. The Aviation Color Code remained at Yellow.

SVERT reported that a thermal anomaly over Snow, a volcano of Chirpoi, was detected in satellite images on 26 December. Cloud cover obscured views on the other days during 23-30 December. The Aviation Color Code remained at Yellow.

SVERT reported that a thermal anomaly over Snow, a volcano of Chirpoi, was detected in satellite images during 12-13 and 15 December. Cloud cover obscured views on the other days during 10-16 December. The Aviation Color Code remained at Yellow.

SVERT reported that steam-and-gas emissions from Snow, a volcano of Chirpoi, were detected in satellite images drifting 90 km SE on 25 November. A thermal anomaly was detected during 27-28 November. The Aviation Color Code remained at Yellow.

SVERT reported that a thermal anomaly from Snow, a volcano of Chirpoi, was detected in satellite images during 4-6 November. Weak steam-and-gas emissions were detected on 4 and 6 November. The Aviation Color Code remained at Yellow.

SVERT reported that steam-and-gas emissions from Snow, a volcano of Chirpoi, were detected in satellite images during 29 and 31 October. A thermal anomaly was detected during 2 and 3 November. The Aviation Color Code remained at Yellow.

SVERT reported that a thermal anomaly from Snow, a volcano of Chirpoi, was detected in satellite images on 12 August, along with gas-and-steam emissions. Cloud cover prevented observations during 13-18 August. The Aviation Color Code remained at Yellow.

SVERT reported that a thermal anomaly over Snow, a volcano of Chirpoi, was detected in satellite images during 5-7 and 9 August, and possibly during 10-11 August. Steam-and-gas emissions were detected on 9 August. The Aviation Color Code remained at Yellow.

SVERT reported that a weak thermal anomaly over Snow, a volcano of Chirpoi, was detected in satellite images during 12-13 April; cloud cover prevented observations of the volcano on other days during 8-15 April.

SVERT reported that a weak thermal anomaly over Snow, a volcano of Chirpoi, was detected in satellite images on 6 April; cloud cover prevented observations of the volcano on other days during 1-8 April.

SVERT reported that a weak thermal anomaly over Snow, a volcano of Chirpoi, was detected in satellite images on 14 March; cloud cover prevented observations of the volcano on other days during 11-18 March.

SVERT reported that steam-and-gas emissions from Snow, a volcano of Chirpoi, were detected in satellite images on 5 March; cloud cover prevented observations of the volcano on other days during 4-11 March.

SVERT reported that weak steam-and-gas emissions from Snow, a volcano of Chirpoi, were observed on 25 February, and 1 and 3 March. A thermal anomaly was detected in satellite images on 28 February and 3 March. Cloud cover prevented observations of the volcano on other days during 25 February-4 March. The Aviation Color Code was Yellow.

SVERT reported that a thermal anomaly and weak steam-and-gas emissions from Snow, a volcano of Chirpoi, were detected in satellite images during 19 and 22-23 February; cloud cover prevented observations of the volcano on other days during 18-25 February. The Aviation Color Code was Yellow.

SVERT reported that a thermal anomaly and weak steam-and-gas emissions from Snow, a volcano of Chirpoi, were detected in satellite images during 14-15 February; cloud cover prevented observations of the volcano on other days during 11-18 February. The Aviation Color Code was Yellow.

SVERT reported that a thermal anomaly and steam-and-gas emissions from Snow, a volcano of Chirpoi, were detected in satellite images on 7 and 10 February; cloud cover prevented observations of the volcano on other days during 4-11 February.

SVERT reported that steam-and-gas emissions from Snow, a volcano of Chirpoi, were detected in satellite images on 1 February; cloud cover prevented observations of the volcano on other days during 28 January-4 February.

SVERT reported that a thermal anomaly and steam-and-gas emissions from Snow, a volcano of Chirpoi, on 8 January, were detected on 21, 23, and 25 January; cloud cover prevented observations of the volcano on other days during 22-28 January.

SVERT reported that a thermal anomaly was detected over Snow, a volcano of Chirpoi, on 8 January, and steam-and-gas plumes were detected on 9 and 11 January; cloud cover prevented observations of the volcano on other days during 7-14 January.

SVERT reported that a thermal anomaly was detected over Snow, a volcano of Chirpoi, during 24-25, 28, and 30 December; cloud cover prevented observations of the volcano on other days during 24-31 December.

SVERT reported that a thermal anomaly was detected over Snow, a volcano of Chirpoi, during 17, 19, and 21-22 December. A steam-and-gas plume was observed on 19 December. Cloud cover prevented observations of the volcano on the other days during 10-17 December.

SVERT reported that a thermal anomaly was detected over Snow, a volcano of Chirpoi, during 11 and 13-15 December. A steam-and-gas plume was observed on 15 December. Cloud cover prevented observations of the volcano on other days during 10-17 December.

SVERT reported that a thermal anomaly was detected over Snow, a volcano of Chirpoi, during 26-28 November; cloud cover prevented observations of the volcano on other days during 29 November-2 December.

On 6 November 1986, weak fumarolic activity was observed during an aerial survey (SEAN 12:04). The Sakhalin Volcanic Eruption Response Team (SVERT) noted that emissions were again observed in November 2012. This report covers steam-and-gas plumes and emissions and thermal alerts between 20 November 2012 and 30 April 2014.

SVERT's monitoring of Chirpoi is hampered by the lack of surface instruments or seismic network. The volcano is primarily monitored by satellites; cloud cover, however, often prevents space-borne observations. The location of Chirpoi in the Kuril Islands is shown in figure 1.

Figure 1. Map showing location of Chirpoi. Courtesy of Google Earth.

SVERT reported thermal anomalies at a volcano of Chirpoi called Snow, starting on 17 November 2012. Periods of steam-and-gas began on 15 December 2012. This activity continued through at least April 2014, based upon analysis of satellite images (table 1). Cloud cover often obscured views of the volcano.

Table 1. Steam-and-gas plumes and emissions from Snow, a Chirpoi volcano, between 21 November 2012 and 30 April 2014, based on analysis of satellite images. Cloud cover frequently prevented observations. Courtesy of SVERT.

Year

Dates

Plume drift

2012

15 and 19 Dec

na

2013

9 and 11 Jan

na

2013

1, 7, 10, 14-15, 19-22, 25 Feb

na

2013

1, 3, 5 Mar

na

2013

23-Jul

na

2013

9 and 12 Aug

na

2013

22-23, 29-31 Oct

na

2013

4, 6, 25 Nov

Drifted 90 km SE on 25 Nov

2014

15, 20, and 27 Mar

na

2014

13-Apr

na

A search of MODVOLC thermal alerts at Chirpoi since 1980 found no such alerts until a they began at Snow on 11 November 2012. Between that date and 24 December 2012, many thermal alerts were reported. According to SVERT, this may have indicated a lava flow on the SE flank. No further alerts were reported until 8 July 2013; between 8 July and October 2013, thermal alerts were issued on six days. The only alerts between November 2013 and 30 April 2014 were on 10 March, 27-28 March, and 14, 16, 18, 21, 27, 29-30 April 2014.

Based on SVERT weekly reports on 12 and 19 November 2012, the Aviation Color Code increased from Green to Yellow between 5 and 19 November 2012, and remained Yellow through at least April 2014. (Green indicates a normal, non-eruptive state; Yellow indicates elevated unrest above background level.)

Geological Background

Chirpoi, a small island lying between the larger islands of Simushir and Urup, contains a half dozen volcanic edifices constructed within an 8-9 km wide, partially submerged caldera. The southern rim of the caldera is exposed on nearby Brat Chirpoev Island. The symmetrical Cherny volcano, which forms the 691 m high point of the island, erupted twice during the 18th and 19th centuries. The youngest volcano, Snow, originated between 1770 and 1810. It is composed almost entirely of lava flows, many of which have reached the sea on the southern coast. No historical eruptions are known from 742-m-high Brat Chirpoev, but its youthful morphology suggests recent strombolian activity.

This compilation of synonyms and subsidiary features may not be comprehensive. Features are organized into four major categories: Cones, Craters, Domes, and Thermal Features. Synonyms of features appear indented below the primary name. In some cases additional feature type, elevation, or location details are provided.

Synonyms

Chyornogo

Cones

Feature Name

Feature Type

Elevation

Latitude

Longitude

Brat Chirpoev
Tirihoi
Tirihoigaku
Chirihoi
Chirihoigaku

Stratovolcano

724 m

46° 28' 0" N

150° 48' 29" E

Cherny
Io San
North Brother

Stratovolcano

624 m

46° 31' 30" N

150° 52' 30" E

Snow
Snou

Stratovolcano

400 m

46° 31' 0" N

150° 52' 30" E

Photo Gallery

Chirpoi Island contains a half dozen volcanic edifices constructed within an 8-9 km wide, partially submerged caldera. This view from the east shows Snow volcano (left), symmetrical Cherny volcano (center), and eroded Chirpoi volcano (right). Cherny volcano, capped by a well-preserved crater, has erupted twice during the 18th and 19th centuries. Snow volcano originated between 1770 and 1810. It is composed almost entirely of lava flows, some of which form the shoreline in the foreground.

Photo by Oleg Volynets (Institute of Volcanology, Petropavlovsk).

Steam clouds rise from the summit crater and fumarolic vents on the upper flanks of Cherny volcano in October 1990. The smooth-sloped cone of Cherny, seen here from the NW, is truncated by a 330-m-wide crater that displays long-term powerful fumarolic activity. Cherny is one of two volcanic cones on Chirpoi volcano that have been active in historical time. Eruptions took place in 1712 or 1713, 1854 (this may have been from the neighboring Snow lava cone, visible at the upper right), and 1857.

References

The following references have all been used during the compilation of data for this volcano, it is not a comprehensive bibliography. Discussion of another volcano or eruption (sometimes far from the one that is the subject of the manuscript) may produce a citation that is not at all apparent from the title.

WOVOdat is a database of volcanic unrest; instrumentally and visually recorded changes in seismicity, ground deformation, gas emission, and other parameters from their normal baselines. It is sponsored by the World Organization of Volcano Observatories (WOVO) and presently hosted at the Earth Observatory of Singapore.

EarthChem develops and maintains databases, software, and services that support the preservation, discovery, access and analysis of geochemical data, and facilitate their integration with the broad array of other available earth science parameters. EarthChem is operated by a joint team of disciplinary scientists, data scientists, data managers and information technology developers who are part of the NSF-funded data facility Integrated Earth Data Applications (IEDA). IEDA is a collaborative effort of EarthChem and the Marine Geoscience Data System (MGDS).